Interactive input systems that allow users to inject input into an application program using an active pointer (eg. a pointer that emits light, sound or other signal), a passive pointer (eg. a finger, cylinder or other object) or other suitable input device such as for example, a mouse or trackball, are well known. These interactive input systems include but are not limited to: touch systems comprising touch panels employing analog resistive or machine vision technology to register pointer input such as those disclosed in U.S. Pat. Nos. 5,448,263; 6,141,000; 6,337,681; 6,747,636; 6,803,906; 7,232,986; 7,236,162; and 7,274,356 and in U.S. Patent Application Publication No. 2004/0179001 assigned to SMART Technologies ULC of Calgary, Alberta, Canada, assignee of the subject application, the contents of which are incorporated by reference; touch systems comprising touch panels employing electromagnetic, capacitive, acoustic or other technologies to register pointer input; tablet personal computers (PCs); laptop PCs; personal digital assistants (PDAs); and other similar devices.
Above-incorporated U.S. Pat. No. 6,803,906 to Morrison et al. discloses a touch system that employs machine vision to detect pointer interaction with a touch surface on which a computer-generated image is presented. A rectangular bezel or frame surrounds the touch surface and supports digital cameras at its corners. The digital cameras have overlapping fields of view that encompass and look generally across the touch surface. The digital cameras acquire images looking across the touch surface from different vantages and generate image data. Image data acquired by the digital cameras is processed by on-board digital signal processors to determine if a pointer exists in the captured image data. When it is determined that a pointer exists in the captured image data, the digital signal processors convey pointer characteristic data to a master controller, which in turn processes the pointer characteristic data to determine the location of the pointer in (x,y) coordinates relative to the touch surface using triangulation. The pointer coordinates are conveyed to a computer executing one or more application programs. The computer uses the pointer coordinates to update the computer-generated image that is presented on the touch surface. Pointer contacts on the touch surface can therefore be recorded as writing or drawing or used to control execution of application programs executed by the computer.
U.S. Pat. No. 6,972,401 to Akitt et al. assigned to SMART Technologies ULC, the content of which is incorporated herein by reference in its entirety, discloses an illuminated bezel for use in a touch system such as that disclosed in above-incorporated U.S. Pat. No. 6,803,906 to Morrison et al. The illuminated bezel comprises infrared (IR) light emitting diodes (LEDs) that project infrared light onto diffusers. The diffusers in turn, diffuse the infrared light so that the intensity of backlighting provided over the touch surface by the illuminated bezel is generally even across the surfaces of the diffusers. As a result, the backlight illumination provided by the bezel appears generally continuous to the digital cameras. Although this illuminated bezel works very well, it adds cost to the touch system.
U.S. Pat. No. 6,823,481 to Takekawa discloses a coordinate input/detection device comprising left and right optical units positioned at the bottom corners of a coordinate input/detection area. Retro reflectors are provided along the upper, left and right sides of the coordinate input/detection area. A pen tool having a body that tapers adjacent one end towards a tip can be used with the coordinate input/detection device. The tapered portion of the pen tool body has a retro reflector thereon.
U.S. Pat. Nos. 7,202,860 and 7,414,617 to Ogawa discloses a camera-based coordinate input device allowing coordinate input using a pointer or finger. The coordinate input device comprises a pair of cameras positioned at the upper left and upper right corners of a display screen. The field of view of each camera extends to a diagonally opposite corner of the display screen in parallel with the display screen. Infrared light emitting diodes are arranged close to the imaging lens of each camera and illuminate the surrounding area of the display screen. An outline frame is provided on three sides of the display screen. A narrow-width retro-reflection tape is arranged near the display screen on the outline frame. A non-reflective black tape is attached to the outline frame along and in contact with the retro-reflection tape. A control circuit calculates the coordinate value of a pen tool, pointing to a position within a coordinate detection field, based on video signals output from the cameras and transfers the coordinate value to a computer. The pen tool is a pen having a pen tip member at one end of a pen body. The pen body tapers near the pen tip member. The tapering portion of the pen tip body is surrounded by retro-reflection tape.
In these interactive input systems, depending on the orientation of the pen tool brought towards the input surface, it can be difficult to distinguish between a finger brought into contact with the input surface and the pen tool. If different functionalities are attributed to different types of pointers, not being able to distinguish between pointer types can be problematic.
It is therefore an object of the present invention at least to provide a novel interactive input system and a novel pen tool therefor.